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Aumento de resolução de imagens de ressonância magnética do trato vocal utilizadas em modelos de síntese articulatória
(Universidade Federal de São Carlos, 2011-10-31) Martins, Ana Luísa Dine; Mascarenhas, Nelson Delfino d'Ávila; https://lattes.cnpq.br/0557976975338451; https://lattes.cnpq.br/9249940379843542
Articulatory Synthesis consists in reproducing speech by means of models of the vocal tract and of articulatory processes. Recent advances in Magnetic Resonance Imaging (MRI) allowed for important improvements with respect to the speech comprehension and the forms taken by the vocal tract. However, one of the main challenges in the field is the fast and at the same time high-quality acquisition of image sequences. Since adopting more powerful acquisition devices might be financially inviable, a more feasible solution proposed in the literature is the resolution enhancement of the images by changes introduced in the acquisition model. This dissertation proposes a method for the spatio-temporal resolution enhancement of the obtained sequences using only digital image processing techniques. The approach involves two stages: (1) the temporal resolution enhancement by means of a motion compensated interpolation technique; and (2) the spatial resolution enhancement by means of a super resolution image reconstruction technique. With respect to the temporal resolution enhancement, two interpolation models are compared: linear interpolation considering two adjacent images and cubic splines interpolation considering four contiguous images. Since both models performed equally in the experiments, the linear interpolation was adopted, for its simplicity and lower computational cost. The initial goal of the spatial resolution enhancement was an extension of the candidate s approach proposed in her master s thesis. Adopting a maximum a posteriori probability approach (MAP), the high-resolution images were modeled using the Markov Random Fields (MRF) Generalized Isotropic Multi-Level Logistic (GIMLL) model and the Iterated Conditional Modes (ICM) algorithm. However, even though the approach has presented promising results, due to the dimension of the target problem, the algorithm presented high computational cost. Considering this limitation, an adaptation of the Wiener filter for the super-resolution reconstruction problem was considered. Inspired by two methods available in the literature, three approaches were proposed: the statistical interpolation, the multi-temporal approach, and the adaptive Wiener filter. In all cases, a separable Markovian model and an isotropic model were compared in the characterization of the spatial correlation structures. These models were used to characterize the correlation and cross correlation of observations for the statistical interpolation and the multi-temporal approach. On the other hand, for the adaptive Wiener filter, these models were used to characterize the a priori spatial correlation. According to the conducted experiments, the isotropic model outperformed the separable Markovian model. Besides, considering all Wiener filter-based approaches and the initial approach based on the GIMLL model, the adaptive Wiener filter outperformed all other approaches and was also faster than a single iteration of the GIMLL-based approach.
Modernização sem mudanças: da contagem de cabeças à gestão estratégica de pessoas
(Universidade Federal de São Carlos, 2011-10-31) Souza, Maria Zélia de Almeida; Alves, Francisco José da Costa; https://lattes.cnpq.br/9183120186518337; Última atualização do currículo em 04/06/2010
The major objective of this work was to study how human resources policies contributed to increase productivity in the manual cut of sugarcane in the last two decades. The sucroalccohol sector has undergone deep changes, accelerated after its deregulation, after the extinction of the Sugar and Alcohol Institute - IAA, in 1990. Competitive pressures forced the search for new business strategies in this sector and Human Management was also affected by this new logic in search of competitive advantage. The most significant results of this research reveal that the Human Resources Departments of the productive units in the sucroalccohol sector have gained new configurations and technological sophistication, assuming a more strategic role. The new human management technologies spread through all the areas, including the rural area and, therefore, the sugarcane cutters. However, it should be highlighted that, despite the incorporated technological sophistication diffused in the human appreciation discourse, the human resources policy did not lead to the abolishment of human management practices based on the well known binomium: prize/punishment; on the contrary, these practices are witnessed throughout all the processes of the sugarcane cutters management, starting at their hire, as well as during their training period, payment and dismissal. What establishes the difference between the modern mode from the traditional one is the logic that justifies the prize and the punishment: logic based upon assessment metrics, often praised as being modern and not subject to protectionism. In practice, these human management actions consist of powerful instruments of control and adequation of the sugarcane cutter to meet the requirements of the productive process, aiming at increasing work productivity through mechanisms which cause the cutter work to be more straining and precarious.